Quick, how do you wire up an SPI bus between a microcontroller and a peripheral? SCK goes to SCK, MISO goes to MISO, and MOSI goes to MOSI, right? Yeah. You’ll need to throw in a chip select … ...

2) Display information to LCDs controlled by your Arduino. 3) Be programmed to act as an extensive combination lock 4) Offer commands, such as ENTER, LOAD, CLEAR, etc.

SPI transactions became officially part of Arduino SPI library some time ago. This happened after many months (most of 2014) of lengthy discussion and testing for these and MANY other details.